title: Changes in cytochrome P450 enzymes by 1,1-dichloroethylene in rat liver and kidney.
abstract: We examined the effect of 1,1-dichloroethylene (1,1-DCE) on microsomal cytochrome P450 (P450) enzymes in rat liver and kidney. Rats were treated intraperitoneally with 1,1-DCE daily for 4 days, at doses of 200, 400, and 800 mg/kg. Among the P450-dependent monooxygenase activities in liver microsomes, testosterone 2alpha-hydroxylase (T2AH), which is associated with CYP2C11 activity, was remarkably decreased by 800 mg/kg 1,1-DCE. The level relative to control activity was < 10%. Furthermore, immunoblotting showed that 1,1-DCE (> or = 400 mg/kg) significantly decreased CYP2C11/6 protein levels in liver microsomes. In addition, 7-methoxyresorufin O-demethylase (MROD), 7-ethoxycoumarin O-deethylase (ECOD), benzphetamine N-demethylase (BZND), chlorzoxazone 6-hydroxylase (CZ6H), and testosterone 6beta-hydroxylase (T6BH) activities were significantly decreased by the highest dose of 1,1-DCE (by 40-70%). However, the activities of other P450-dependent monooxygenases, namely 7-ethoxyresorufin O-deethylase (EROD), 7-benzyloxyresorufin O-debenzylase (BROD), aminopyrine N-demethylase (APND), erythromycin N-demethylase (EMND), lauric acid omega-hydroxylase (LAOH), and testosterone 7alpha-hydroxylase (T7AH) were not affected by 1,1-DCE at any dose. Immunoblotting showed CYP1A1/2, CYP2B1/2, CYP2E1, and CYP3A2/1 protein levels were significantly decreased by 60-66% by 1,1-DCE (800 mg/kg), whereas that of CYP4A1/2 was not affected by any dose of 1,1-DCE. By contrast, among the P450-dependent monooxygenase activities in kidney microsomes, only CZ6H activity was increased by 1,1-DCE (1.6-fold at 800 mg/kg). Also, it was observed that 1,1-DCE (800 mg/kg) significantly increased CYP2E1 protein levels by immunoblotting (approximately 1.5-fold). These results suggest that 1,1-DCE changes the constitutive P450 isoforms in the rat liver and kidney, and that these changes closely relate to the toxicity of 1,1-DCE.
authors.affiliation: Division of Environmental Chemistry, National Institute of Health Sciences, Kamiyoga, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Hanioka
authors.forename: H
authors.initials: H
authors.lastname: Jinno
authors.forename: T
authors.initials: T
authors.lastname: Nishimura
authors.forename: M
authors.initials: M
authors.lastname: Ando
mesh_terms: D015660:7-Alkoxycoumarin O-Dealkylase / Q000032:analysis; D000633:Aminopyrine N-Demethylase / Q000032:analysis; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D001711:Biotransformation; D001835:Body Weight / Q000187:drug effects; D019363:Cytochrome P-450 CYP1A1 / Q000032:analysis; D019362:Cytochrome P-450 CYP2B1 / Q000032:analysis; D019392:Cytochrome P-450 CYP2E1 / Q000032:analysis*; D051544:Cytochrome P-450 CYP3A; D042926:Cytochrome P-450 CYP4A; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis*; D000072467:Cytochrome P450 Family 2; D004000:Dichloroethylenes / Q000493:pharmacokinetics / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D015151:Immunoblotting; D007527:Isoenzymes / Q000032:analysis*; D007668:Kidney / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D008565:Membrane Proteins; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000032:analysis; D009247:NADH, NADPH Oxidoreductases / Q000032:analysis; D009251:NADPH-Ferrihemoprotein Reductase; D009929:Organ Size / Q000187:drug effects; D010088:Oxidoreductases / Q000032:analysis; D010089:Oxidoreductases, N-Demethylating / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D039181:Steroid 16-alpha-Hydroxylase; D013250:Steroid Hydroxylases / Q000032:analysis
chemical_list: D004000:Dichloroethylenes; D007527:Isoenzymes; D008565:Membrane Proteins; C029297:vinylidene chloride; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; C076307:methoxyresorufin-O-demethylase; D013250:Steroid Hydroxylases; D015660:7-Alkoxycoumarin O-Dealkylase; D019392:Cytochrome P-450 CYP2E1; D001189:Aryl Hydrocarbon Hydroxylases; C450279:CYP2C11 protein, rat; C465260:Cyp3a2 protein, rat; D019363:Cytochrome P-450 CYP1A1; D019362:Cytochrome P-450 CYP2B1; D051544:Cytochrome P-450 CYP3A; D000072467:Cytochrome P450 Family 2; D039181:Steroid 16-alpha-Hydroxylase; C019781:benzphetamine N-demethylase; D042926:Cytochrome P-450 CYP4A; D010089:Oxidoreductases, N-Demethylating; D000633:Aminopyrine N-Demethylase; D009247:NADH, NADPH Oxidoreductases; D009251:NADPH-Ferrihemoprotein Reductase